1. Field of the Invention
This invention relates to using CMP, chemical mechanical polishing, to planarize substrates having trenches used for shallow trench isolation or for a metal damascene structure.
2. Description of the Related Art
U.S. Pat. No. 4,962,064 to Haskell et al. describes a method of planarizing a substrate having filled trenches formed therein. The trenches are filled with two materials such as a layer of an oxide followed by a layer of polysilicon. After filling the trenches a CMP step is followed by an etching step to produce a planar substrate.
U.S. Pat. No. 5,362,669 to Boyd et al. describes a method of planarizing a substrate having filled trenches formed therein. A first CMP resistant layer is formed on a substrate. The trenches are then formed in the substrate followed by the deposition of a layer of dielectric. A second layer of CMP resistant material is then deposited having the same thickness as the first CMP resistant layer. The substrate is then planarized using CMP.
U.S. Pat. No. 4,957,881 to Crotti describes methods of forming self aligned contacts. The methods comprise planarization of the substrate using etching methods.
U.S. Pat. No. 5,380,546 to Krishnan et al. and U.S. Pat. No. 5,451,551 to Krishnan et al. describe methods of planarizing a substrate for multilevel metallization processes. The methods comprise protecting a metal feature using barrier materials prior to planarization of the substrate.
A Patent Application (CS-97-043) entitled "A METHOD TO AVOID DISHING IN FORMING TRENCHES FOR SHALLOW TRENCH ISOLATION" Serial No., Filed, and assigned to the same Assignee describes a method of filling trenches with a dielectric which is formed at a greater rate within the trench than outside of the trench.